MySQL is not SQL Server, so the solutions are a little different but the cause of the question marks is the same. What you are seeing is a character conversion error which can happen in any point in your request/response chain.

Microsoft SQL Server introduced NCHAR, NVARCHAR, and NTEXT to handle unicode. These are all Microsoft specific keywords so they won't work with MySQL. These days, MySQL should be set up to handle unicode character sets by default, but just in case you may want to check out these links: